Power case-shift mechanism



H. C. YAEGER POWER CASE-SHIFT MECHANISM Jan. 10, 1956 2 Sheets-Sheet 1Filed Feb. 10, 1953 lNl/ENTOR HARRY C. V4565? TTORNEV Jan. 10, 1956 H.c. YAEGER POWER CASE-SHIFT MECHANISM 2 Sheets-Sheet 2 /Nl EN7OR HARRY CMEG/ER By w WM;

ATTORNEY Filed Feb. 10, 1953 PQWER SASE-SHIFT MECHANISM Harry C. Yaeger,West Hartford, Conn., assignor to Underwood \Corporation, New York, N.Y., a corporation of Deiaware Application February 10, 1953, Serial No.336,091 6 Claims. (Cl. 197-74) This invention relates to typewritingmachines and more particularly to case-shifting mechanism for suchmachines. The subject matter is a continuation-in-part of my applicationSerial No. 258,853, filed November 29, 1951, now Patent No. 2,681,720,issued June 22, 1954, as a division of application Serial No. 199,306,filed December 5, 1950, now Patent No. 2,703,641, issued March 8, 1955.

In most typewriting machines the type-bearing instrumentalities arecase-shiftable relatively to paper supporting means, in order tocondition the machine for typing by different case types. Regardless ofwhether such relative shift is accomplished by a shift of the papersupporting means or a shift of the type-bearing instrumentalities, thereexists the problem of quickly setting in motion and arresting aconsiderable case-shift mass in an interval of time which must be veryshort for speedy operation of the machine. Furthermore, it is mostdesirable to effect the case-shifts with a minimum of attendant shockand noise.

it is therefore an object of the invention to provide an efiicient,quickly, smoothly and quietly operating caseshifting mechanism.

it is a further object of the invention to provide a power-operated,case-shift mechanism which will operate with a minimum of applied motorpower, smoothly and substantially noiselessly.

Also an object of the invention is to provide in eflicient cooperationwith a case-shift means which may include power means, an efiicientcase-shift cushioning device which during cushioning action stores asubstantial amount of energy, and which beneficially applies such storedenergy to aid a succeeding motor-operated case-shift operation.

Other objects and features of the invention will be in part obvious andin part pointed out particularly as the following description of apreferred embodiment of the invention proceeds.

The invention is illustrated in association with a pressure printingtyping mechanism which is the subject of the aforementioned patentapplication Serial No. 199,306, and which embodies a pivotallycase-shiftable type carrier I system.

Turning now specifically to the drawings:

Figure l is a fractional right-hand side elevation of a typewritingmachine showing the power case-shifting mechanism of the invention inits normal, lower case condition, and idle,

Figure 2 is a fractional side elevation similar to Figure l, but thepower case-shifting mechanism is shown in an upper case condition,

Figure 3 illustrates two device.

Referring now more particularly to Figure l, the machine to which theinvention is applied comprises two main side plates or walls 18. Betweenthese side walls there is case-shiftably supported on pivot studs 34provided on the opposite machine walls 18, a body or unit parts of aspring supporting nited States Patent 2,730,224 Patented Jan. 10, 195630 having thereon a system of type carriers 40. The individual typecarriers 40 are selectively operable under key control to type against ausual work-sheet supporting platen 24. The case-shiftable body 30includes adjacent the inside of each machine Wall 18 a side plate 33,these plates being connected by various members including one numbered188.

The said case-shift body 30 is shown in its normal, lower case positionin Figure 1. In this position an arm 181 of each side plate 33 of thecase-shiftable body 30 abuts an eccentrically adjustable normal casestop 182, each such stop being carried on the adjacent side wall 18 ofthe machine. In the stated normal case position of the case-shift body30, the type carriers 40 are selectively operable to type by either oftwo lower case types 51, as indicated by dot-and-dash lines.

In Figure 2 the case-shift body or unit 30 is shown in upper, that is,in capital case position. The arms 181 abut each upwardly against acapital case stop 183 which is similar to and adjustably supported inthe same manner as the normal stop 132. In the stated capital caseposition of the body the type carriers 40 are selectively operable totype by either one of two upper case types 510, as indicated by twodot-and-dash lines in Figure 2.

For moving the case-shift body 30 to and from caseshifted position thereis provided a noiselessly operating power mechanism which in somerespects is similar to a mechanism disclosed in the U. S. Patent toHelrnond, No. 2,275,759, dated March 10, 1942. This power mechanismincludes a normally quiescent eccentric having associated therewith, bymeans of a ring of balls 197, a connecting rod 196, said balls beingaccommodated in opposite ball races provided in the eccentric 195 andthe connecting rod 196, whereby said eccentric is turnable with aminimum of friction in the connecting rod and the latter is retained onthe eccentric. The connecting rod has a pivotal connection with a rocker198 that is pivotally carried at 200 on the left side wall 18 of themachine frame. The rocker has adjustable abutments 201 straddling a pin202 extending laterally from a down-reaching portion of the left endplate 33 of the case-shift body 30. The pin 202 extends through aclearance hole in said side wall 33. The eccentric 195 is turnablymounted on a shaft 203, the latter of which is constantly rotating whenthe machine is in use and carries fast on the outer end thereof,adjacent the eccentric 195, a toothed rotor or clutch wheel 204.Provision is made to couple the eccentric 195 to said toothed wheel 204to be turned thereby a half turn upon downward operation of a shift key205 and to be turned another half turn upon restoration of such shiftkey. A clutch pawl 2136 pivotally carried on the eccentric 195 isnormally held free of the toothed wheel 294 by a control dog 207 thatnormally engages an outreaching nose of the pawl. A compression spring208 carried in a portion of the eccentric engages a tail of the pawl 206and thereby tends to swing the pawl inwardly into coupled associationwith the wheel 204. Diametrically opposite to the control dog 207 thereis another control dog 210 which when the case-shift key is in normalposition is clear of the orbit of the pawl 206. The two dogs 207, 210are each pivotally carried as at 212 on a bracket 211. A link 213connects the two dogs. The case-shift key 205 is borne on a lever 209fast on a shaft 214 and when said key is operated an arm 215 on the leftend of the shaft 214 draws a link 2116 forwardly. The latter has apivotal connection with the dog 210 and upon operation of the shift key205 will swing the dog 210 into the orbit of the out-reaching nose ofthe pawl 206. At the same time due to the link 213 Which connects thetwo dogs, the dog 207 will swing clear of the nose of the pawl 206,where'- fore the eccentric 195 becomes coupled to the toothed wheel 204to turn therewith. At the end of a half turn the eccentric 195connecting rod 196 will be in the rearward. position seen in Figure 2,and through operation of the rocker 198 will have displaced thecase-shift body 30 to the upper case position. The half turn of theeccentric is terminated by engagement of the outreaching nose of thepawl 206'with the hooked end' of the dog 210, such engagement resultingin a limited outswinging movement of thepawl to'free the latter from thetoothedwheel 204 as shown in Figure 2. At-thereleas'e of the case-shiftkey 205 the dogs 207, 210, under the tension of a spring 217 associatedwith the link 216, return to their normal positions seen in Figure 1.Consequently the pawl 266 will reengage the toothed wheel2'04'for'a'seeond half turn of the eccentric 195, such half turn beingterminated as the pawl 206 is intercepted by thedog2fi7 and swung clearof the wheel'294. During such second half turn the connecting rod 1% 'isdriven forwardly by the eccentric and through restoration of the rocker198'will'restore the case-shift body 36 to the normal case position seenin Figure l. The motion imparted-to'the connecting rod 196 is ofharmonic characteristic and, as will become evidehthereinafter, a strongresilient means associated with the heavy case-shift body 30 andstrained in the half part downward movement exclusive of a first partdownward movement is an important'cooperative factor in a cooperativeorganization whereby said'heavy case-shift body is smoothly picked up ineach case position, smoothly moved, and deposited in the other caseposition with the least attendant shock and noise. Also thedisengagement of the pawl 2&6 from the wheel 20 2-, and the arrest ofthe eccentric 195 is achieved without shock and noise, but this featureis the subject matter of application Serial No. 258,853, hereinbeforenoted. Briefly stated, the dogs 29'], 210 yield slightly when'they areengaged by the clutch pawl 266, such yield being afforded by leafsprings 218 of gooseneck form. Moreover, as shown in reference to thedog 207,

the gooseneck spring 218 may be backed up by a'relatively solid abutment220 which is normally spaced slightly from said spring. The oppositerange of movement of the dogs is controlled by two stop pins 219. Due tothe resiliency of the gooseneck spring 218, the eccentric 195 has atendency to rebound in reverse direction as the pawl 206 isinterceptedat each half turn of the eccentric. To control this rebounding tendency,the eccentric 195 carries 'fast thereon a two-lobe member 223 with whichthere cooperates a spring pressed pawl 224.

Whilethemachine is in use, the shaft 203 is preferably continuouslymotor-driven at a desired case-shift speed.

The case-shift body 30, along with all the mechanism thereon, representsan appreciable mass, and because it must be moved from one case positionto the other in a very short interval of time, there arises the problemof attendant shock, noise and rebound. it is old and 'well known in theart to provide spring means substantially to counterbalance the mass ofa case-shift body, but in a downward shift the'acceler'ation of the bodydue to gravitation soon assumes such magnitude that the force ofmomentum of the body will over-power decisively ordinarycounterbalancing spring means. Resultin'gly, the substantial case shiftmass under the conditions stated cannot be controlled and broughtto restas smoothly and quietly as desired. Moreover, in the first half of theupward's'hift the substantial mass of the body is a strong opposingfactor conducive to harshness of operation and strain. Merely to providea counterbalancing spring is therefore not a solution toward providingamost eihcie'nt, smooth and shockless case-shift operation.

Now with more specific reference to the power operating eccentric 195shown in the drawings, it is to be noted that the clutch 204, 286therefor is one-way driving, for ease, speed and reliability ofengagement, and that the under a condition of permitted excessivegravitational influence "of the case-shift body, through a 'piillontheconneet-ing'rod196, will be driven and-accel- "e r'ate'd to exceedthe s'p'eed of the toothed driving wheel 204., That is ,to, say, themotion of the eccentric will cease to be controlled by the speed ofoperation of the toothed drive wheel 204 and will have a run-awaycharacteristic. Obviously, under the stated condition there cannotprevail a smooth and controlled movement of the heavy case-shift body,conducive to smooth, shockless and noiseless case-shift operation.

According'to the-invention the gravitational acceleration of thecase-shift body, after an initial, relatively free movement has beenallowed to take place, is thereafter counteracted by the straining of astrong resilient means. In the embodiment of the invention shown, theresilient means is in the form of a strong compression spring 236 thatis strained over the second half of the downward movement of thecase-shift body 36. The opposition to movement so provided for preventsa runaway gravitational movement of the case-shift body 30 in the secondhalf of the downward shift, while on the other hand initially thereprevails a low resistance to movement to 'allow the case-shift mass toget smoothly under way. Moreover, the strong spring in being strained,stores a significant amount of energy as the case-shift body 30 ispower-driven to its lower position at harmonic motion characteristic bythe eccentric 195. Subsequently when the eccentric 195 thereafter isturned to shift the body 30 to its upper position, the energy stored inthe strong spring 236 asserts itself to aid the movement of the body andrelieve operational strain, it being noted however that the eccentric195 needs to move first-appreciably from dead center position for theeherg'y 's'toringsprin'g 236 to exert its beneficial action to lessenthe resistance'to rotation of the eccentric 195.

In the specific embodiment of the invention illustrated, thesaidstrong-spring 236 is a compression spring and is part of a spring unitor device 226 which may embody also a relatively weak compression spring235. There may be a spring device 226 on each side of the machine butaccording to the preferred embodiment of the invention shown, there isonly one on the side of the poweroperable case-shift rocker 198. Thestated spring device 226coin'pris'es an upper and a lower link member227, 228 respectively, having forked portions 230, see Figure 3,'iriterfittihg one another to allow their distention lengthwise. Theupper link member 227 has a pivotal joint with the overlying arm 181 ofthe case-shift body as at 231, while the lower link 228 has a forkedlower end fitting in -anotched bottom of an opening 232 in the sideplate 18 of themachine. Each of the two links 227, 228 is shouldered asat 233 for spring seating elements 234 to abut ther'eag'ainst. Therelatively light compression spring 235 is loosely accommodated on thelink members 227, 228, and interposed in compression between the twoseats 234 exerting a light upward force on the case-shift body 30'elibsfaiitially balancing merely its aggregate weight. The springdevice 226 embodies the stronger compressio'h s'pi'ii1'g-236 between thetwo spring seats 234 in [a loosely surrounding relation to the lighterspring 235. The heavy spring 236 with the case-shift body residing inupper position is'shorter than the space between the two spring seats234 to an extent so that such spring commences to be strain'edapproximately when one-half 'of the downward movement of the case-shiftbody 30 from upper to lower position has taken place. By that time thecase "shift =hody has assumed high speed and the gravitational influencethereon vigorously tends to increase its speed. -Howeve'r, it will beevident that in the second half part of the downward movement of thebody 30 the heavy spring 236 opposes strongly the gravitaaerial-runawatendency of the body, causing it to move at a smooth controlled pace andpreventing it from drivihg the ecceiitr ic 195 a: a speed in excess ofthe powerdriv'nttiothed wheel 204. The downward shift of the body 30 isthiisacoinplished with smoothness and ease. At tlie sarhe tiiii'e, inbeing strained, the heavy spring 236 "st'ores an iinportaiit amount ofenergy which in the operation of the eccentric 195 to eifect an upwardshift of the body 30, after an initial movement from dead centerposition, asserts itself eflectively and beneficially to aid the upwardshift of the body and make the rotation of the eccentric easier, therebylightening the load on the motor and generally contributing to smootheroperation. It will be noted that the ececntric 195 forces the case-shiftbody 30 to normal case, lower position against the resistance of theheavy spring 236 which is conducive to snubbing such movement. At theend of such movement the case-shift body 30 is held stationary becausethe eccentric 195 reaches and is arrested in dead center position, andbecause the check pawl 224 in cooperation with the load member 223prevents backward rotation of the eccentric 195.

Since the lighter spring 235 merely balances substantially the weight ofthe case-shift body 30 inclusive of the mechanism supported thereon, itfollows that in a poweroperated case-shift movement of said body toupper, capital case position, the eccentric 195 works with great ease.The body upon arrival in upper case position is held thereat due to thedead center position reached by the eccentric 195, see Figure 2. Whenthe eccentric 195 receives a half turn to case-shift the body 30 down tothe normal case position seen in Figure 1, it follows that anappreciable first-part movement of the case-shift body 30 is againstvery little resistance.

Due to the structure cooperative hereinabove described the motor powercan be kept to a minimum and the case shift movement in either directiongets under way and is accomplished against smoother effectiveresistance, reducing shock and noise. This in turn makes feasible ahigher speed of power operation for the eccentric 195 than otherwisewould be practically feasible for the same case-shift mass.

Obviously the eccentric stops 182, 183 associated with the arms 181 ofthe case-shift body 30 are adjusted for proper correlation so that whenthe eccentric 195 is in either of its opposite dead center positions thearms 181 will firmly engage the appropriate eccentrics.

It is understood that the invention may take other forms than that shownand that for example a single spring may be provided havingsubstantially the combined characteristic of the two springs 235, 236.

Obviously also the invention is not restricted to caseshifting apivotally mounted case-shift body, nor to caseshifting a type systeminstead of a carriage. It is also understood that the case-shiftoperating mechanism may take other forms than that shown. In general,variations of the structure may be resorted to within the scope of theinvention and portions of the improvement may be used without others.

What is claimed is:

1. In a typewriting machine having a case-shift body mounted fordownward and upward case-shifts between an upper and a lower position,flexibly strainable means arranged to oppose downward shift of saidbody, comprising relatively easily flexible spring-turns approximatelycounterbalancing the weight of the body to resist moderately the body ina first part downward shift, and comprising also relatively much harderstrainable spring-turns to resist heavily the body substantiallythroughout the second half of the downward shift but exclusive of anappreciable first part of the downward shift, whereby said harderstrainable spring-turns store a significant amount of energy in thedownward shift of the body, and harmonic motion means controllable toshift said body from either of said positions to the other and to holdit there, said harmonic motion means, resultant to shifting the body tolower position, being effective to hold said harder strainablespring-turns against effectively acting upwardly on said body, andconsequential to starting the shift of said body from said lower to saidupper position enabling said harder strainable spring-turns to exertenergy stored therein to assist effectively and strongly thereafter theupward shift of thebody substantially not less than half-way toward theupper position.

2. In a typewriting machine having a case-shift body mounted fordownward and upward case-shifts between an upper and a lower position,abutment means directly associated with said body to stop it oppositelyin its shifts to its upper and its lower position, flexibly strainablemeans arranged to oppose downward shift of said body, comprisingrelatively easily flexible spring-turns approximately counterbalancingthe weight of the body to resist moderately the body in a first partdownward shift, and comprising also relatively much harder strainablespringturns to resist heavily the body substantially throughout thesecond half of the downward shift, but exclusive of an appreciable firstpart of the downward shift, whereby said harder strainable spring-turnsstore a significant amount of energy in the downward shift of the body,and harmonic motion power means to shift said body from either of saidpositions to the other against said abutment means and to hold it there,said harder strainable spring-turns, consequential to initial movementof said harmonic motion power means in effecting the shift of the bodyfrom said lower to said upper position, becoming automatically enabledto exert beneficially the energy stored therein to assist effectivelyand strongly thereafter the upward shift of the body substantially notless than half-way toward the upper position.

3. In a typewriter having a case-shift body mounted for movement betweenan upper and a lower case position, spring means associated with saidbody and of a character to counterbalance substantially said body whenit is stationed in upper position and in a second half part downwardmovement exclusive of a first part downward movement being strained toresist heavily the downward movement of the body and storing energy indoing so, means to shift said body from each one to the other of thesaid two positions and including a harmonic motion device to drive saidbody to and from lower position with harmonic motion action, and indriving it to lower position holding it there, said spring meansconsequential to initial movement of said harmonic motion device toeffect the shift of the body from said lower to said upper positionbecoming automatically enabled to exert beneficially the energy storedtherein to assist effectively and strongly the upward shift of the bodysubstantially not less than half-way toward the upper position.

4. In a typewriter having a case-shift body mounted for movement betweenan upper and a lower position, strong flexible means associated withsaid body to resist the movement of said body strongly throughout thesecond half of its downward movement but having no movement-resistingaction on the body during an appreciable first-part downward movement ofsuch body, and power means controllable to drive said body oppositelyfrom each of the said positions to the other and hold it there,including, a motor-operable rotor, a harmonic motion device and aone-way clutch by which said rotor is capable to drive said harmonicmotion device, said harmonic motion device adapted to drive said body tosaid lower position ending in harmonic motion action thereon andreversely adapted to drive it from said lower position with harmonicmotion action, said body in being driven to said lower positionstraining said strong flexible means and said harmonic motion meansafter driving said body to said lower position being effective to holdit there against the upward urge which said strained flexible meansexerts on said body, the said harmonic motion device, consequential todriving said body an initial part upwardly, enabling said strongflexible means to exert beneficially the energy stored therein to assiststrongly the upward drive of said body by said harmonic motion devicetoward said upper position and not less than half-way toward such upperposition.

5. In a typewriter having a case-shift body mounted for movement betweenan upper and a lower position,

spring means associated fbody ja'na :of a 'character to counterbalance-"substantia1ly ,"said body when it isst'atioiied in'said upperpositionfand'ina half part downward movement'exclusiveot -a firstpmdownwarduhovemengbeing strained to resist heavily the downwardmovement of said body andst'oring energy in doing so, and means to movesaid body 'oppositely'froin either of said positions to theother,'including, "a motor-driven rotor, a displacement elementconnectable for operation by said rotor to operate 'said body'from saidup per to said lower position and having provision to move said bodyat'rapidly diminishing speed throughout the lower half of its downwardmbvrne ritfand a one way drive elutch controllable to connectsaidelement for rotation by said rotor to eifect'rnove'r'nent ofsaid bodyfrom-said upper to said lower position and also controllable to effectmovementof said body from said lower to said upper position, saids'pring-means resisting strongly the body in its second half partdownward movement and thereby preventing said'body from exceedin' gtherate of speed at which the rotor isable to drive the body through saiddisplacement element by said one-way drive cluteh, the energy stored insaidspring means after the movement of said body to said lower positionassisting strongly the upward movement of said body about half-waytoward said upper position. v I,

6. In a typewriting machine having "a case-shift body mounted foropposite case-shift movement on a frame to an upper and a lowerposition, a relatively light cornprssive sprin a re atively strongeemp'ressrve spring, thelatt'erhaviiig fin-inside diani'eter larger thanthe outside diameter of the "former and substantially coaxially afrangedfto surround the for'riiierfspring seating means to accommodatesaidlight spring in compression between said frame and sausage-s irtb'ody'to exert always a liftin gforce on s'aid'body, means oppositely onthe frame and's aid body to compress s aid strong spring in theinovement'of said body fromitsiupper to its lowerpositiononly'afterafirstpart of such'iri'oveinent has taken place andsubstantially throughout the 'secondhalf movement, whrebyasigriifieantanioi nt of energy is 'stored in 'saidstrong s'pring'in asecond half movement of the body to said lower position, and means tomove said body from either of said positions to the other and uponmovement of *said "body to either er said positions being instrumentalto hold it there, said body moving means upon eifectin'g initialmovement of said body'toward said upper positio'n'beinginstruiiieiit'al'to cause said strong spring to aid strongly the moement of the body sub stantially half-way toward its flipper position.

References Cited in the'file of this patent UNITED STATES iATE'NTs

